1. Field of the Invention
The present invention relates to a method and an apparatus for simulating and analyzing industrial processes in a laboratory environment or for use in a part of a mass production line of engineered components. More specifically, the present invention provides for a method and apparatus for simulating and analyzing temperature and time dependent industrial thermal processes in a laboratory setting with a high degree of accuracy and repeatability.
2. Description of the Prior Art
The manufacture of metals, alloys or metal matrix composite components is a complex process. It involves a variety of thermal, chemical, and physical mechanisms that influence the structural and mechanical properties of final products. The only effective way to design, analyze, and optimize new and existing industrial thermal processes is to develop a complete quantitative knowledge of and an understanding of the relationships between the process variables and the desired properties of the final products.
One of the fundamental elements in the understanding of the effects of these thermal processes is the examination of the key structural and mechanical properties of products, which were treated by thermal, thermo-physical, thermo-chemical or thermo-electromagnetic processes. Simulating and quantifying the effects of the various thermal process parameters on a resulting work piece structure and determined service characteristics can provide an accurate picture of every important aspect of the given thermal process as mentioned above, including an “energy signature” of the product. The information gained in the given metallurgical experiments can be used to design and optimize industrial thermal procedures that produce products with predefined engineering specifications.
Simulation of industrial thermal processes in a laboratory environment has traditionally been performed using separate melting, liquid metal treatments, heat treatment, and quenching equipment. In most situations, the process optimization is evaluated using the well known metallographic approach. The use of the thermal analysis technique for thermal process optimization is seldom used due to its analytical and experimental limitations (i.e., lack of necessary information for accurate quantitative analysis of metallurgical reactions, thermal hysterisis during the complex thermal processes, . . . etc.). Moreover, industrial and laboratory melting and heat treatment furnaces, including those which are electrical or gas powered are difficult to control and have restricted utility due to their large thermal capacitance and consequently large time constant (i.e., the time and temperature response of the tested work piece). Often there is a considerable difference in the temperature between the work piece and the furnace chamber itself, which can negatively affect the work piece characteristics (e.g., incipient melting). Consequently, it is extremely difficult to optimize quickly any new and sophisticated thermal processes using commercially available laboratory and industrial equipment.
Rapid optimization of new and sophisticated thermal processes is also hindered for other reasons such as the inability to conduct continuous or interrupted melt and work piece(s) heat treatment operations with on-line work piece metallurgical characterization. In addition, the transportation of the work piece, between testing stations, poses a safety hazard and, as well, a loss of continuity for the process itself and for the recorded data, elements vital for the assessment of the process parameters. Finally, because the sample is being moved from station to station, continuous on-line temperature measurement is impossible. Therefore, what occurs within the sample at key stages of the process may become lost in an analytical “black box”. With traditional methods, only final metallurgical characteristics of the entire process can be obtained, rather than the ones developed during individual operations, which would be indispensable for the work piece itself and for thermal process optimization.
Furthermore, laboratory computer and experimental simulations of the industrial thermal processes have frequently been proven inadequate due to the lack of sufficiently high experimental precision; the inability to carry out experiments on sufficiently large test samples in order to perform further physical testing; and because the present day laboratory facilities, in most cases, are unable to replicate and fully control all relevant process variables that are characteristic for the production environment.
In order to satisfy the growing demand by industry for considerably improved products having predetermined performance characteristics, it is necessary to scientifically optimize heat treatment routines for fulfilling the requirements of specific applications. To date, such tasks were performed relying on experimental data from a Differential Scanning Calorimeter (DSC), Conventional Thermal Analysis (CTA) or Differential Thermal Analysis (DTA). However, the microscopic size of the DSC and DTA test samples and their restricted experimental conditions do not allow for metallurgical assessment of an actual industrial casting and the manufacturing process to which it is subjected (i.e., macro segregation, porosity and its distribution, grain size, . . . etc.).
In addition, transformation of laboratory settings to industrial scale production has been difficult as prior art laboratory experiments have not been adequately accurate and could not replicate the multitude of variables in an industrial environment. Advanced process optimization requires a laboratory system with testing, analytical capabilities, and control functions far exceeding those systems currently known in the art.
What is needed therefore is an apparatus that overcomes the difficulties of the prior art. More specifically, such an apparatus is needed that consolidates the capabilities of several instruments into a single apparatus which is easy and less expensive to set up, requires less floor space, has a less demanding maintenance schedule and is safer, by eliminating manual transfers of the test sample (i.e., work piece). Such an apparatus should perform thermal analysis by recording and analyzing the “energy signature” of a test sample with a high degree of accuracy and repeatability.
Still further, what is needed is that such an apparatus should simulate a variety of industrial melt and work piece (s) heat treatment processes and allows for the evaluation of physical properties of the material, such as specific heat, total heat or phase transformation (i.e., latent heat), or the heat of transformations of individual, identifiable reactions during phase transformations. Such an apparatus should be fully programmable and capable of a step change in power input heat source and a wide variety of cooling media, which guarantees the fastest temperature response of the test sample.
Moreover, such an apparatus should have the simulation capabilities and related test sample size, which allows for application of the simulation analysis results directly to full size components. This will reduce the cost and time required for “trial and error” experiments performed in an industrial environment.